Cutter tip holder for roof scratching construction



Dec. 14, 1965 ORR 3,223,451

CUTTER TIP HOLDER FOR ROOF SCRATCHING CONSTRUCTION Filed Dec. 19. 1960 2 Sheets-Sheet 1 V INVENTOR. Fa v O/W F. ORR

Dec. 14, 1965 CUTTER TIP HOLDER FOR ROOF SCRATCHING CONSTRUCTION 2 Sheets-Sheet 2 Filed Dec. 19, 1960 INVENTOR. 37

United States Patent 3,223,451 CUTTER TIP HOLDER FOR ROQF SCRATCEHNG CONSTRUCTION Fay Orr, Oak Grove, M0. Filed Dec. 19, 1960, Ser. No. 76,719 2 Claims. (61. 299-85) This invention relates to machines and mechanisms for scratching or removing gravel and tar from tar and gravel type roofing and refers more particularly to cutting head assemblies and members and mountings for use in such application.

Tar and gravel type roofing is very frequently employed to cover the flat roofs of industrial plants and installations. It is estimated that eighty percent (80%) of all industrial roofing is of the tar and gravel type. Such type roofing conventionally has a ten to twenty year life span. At the end of this period, in order that the building may be adequately reroofed, or sections thereof repaired or replaced, all loose gravel must be removed from the roof whereby to present a smooth reroofing surface. After such gravel removal, new tar and gravel roofing is laid right on top of the old roofing remaining. The adherence of the gravel to the tar over the conventional heavy paper base is often extremely diflicult to remove.

Gravel employed in roofing may vary from conventional railroad gravel to granite chat of great hardness and abrasive characteristics. The basic purpose of the gravel in the roofing is to hold the pitch on the roof in uniform distribution and keep it from running. In aging of the roof, the tar tends to form a gummy layer under the chat or gravel with the latter striating to the top. Eventually, over a period of time, the gravel or chat ends up on the top of the roofing layer. There is generally a relatively soft felt layer under the pitch. Roofing thicknesses may vary as government and community requirements may differ.

The basic goal of the conventional removal process is to attempt to get both the pitch and gravel ofi down to the felt. Generally it is found that all of the pitch cannot be removed, but it is at least necessary to get below the chat or gravel layer. Asphalt roofs generally are much harder to scratch or remove and require harder and longer work.

A basic object of the instant invention is to permit accomplishment with an improved cutting head assembly and cutting head of the greatest amount of effective roof scraping in the shortest time, for example, accomplishing with one machine the work of forty men in a day, that is to say, 100,000 square feet per day, or, 125 squares per hour, with blades lasting 500 squares.

Another object of the invention is to provide a roof abrading cutter head assembly having a plurality of cutter blades or tips thereon each achieving a maximum operating life due to the most efiicient utilization thereof, the cutter blades or tips also continuously self-sharpening through use so that periodic sharpening operations will not be required.

Another object of the invention is to provide a cutter head for a roof abrading device which imitates the action of a spud bar in cutting through the gravel and scooping it free down to the felt, yet not having the limitations nor labor requirements of a spud bar.

Another object of the invention is to provide a cutting head assembly for a roof abrading device which additionally will scrape asphalt roofs successfully despite the greater hardness thereof.

Yet another object of the invention is to provide a cutter or blade mounting on a cutting head for a roof abrading device which provides a double action of first striking the roof in a first position, then rebounding to a second position in order to scrape.

Another object of the invention is to provide a cutting head and cutter or blade construction which provide a greatly increased cutter blade life whereby to permit the processing of some 600 10 x 10 squares as opposed to other available conventional devices which handle less than 100 squares before wearing out.

Yet another object of the invention is to provide an effective cutting head construction for a roof abrading device which permits a high r.p.m. operation whereby to accomplish maximum results in a minimum time.

Other and further objects of the invention will appear in the course of the following description thereof.

In the drawings, which form a part of the instant specification and are to be read in conjunction therewith, embodiments of the invention are shown and, in the various views, like numerals are employed to indicate like parts.

FIG. 1 is a three-quarter perspective view from the front of the roof abrading device, particularly showing the inventive cutting head mounted thereon.

FIG. 2 is a side elevation of a cutter tip holder employable on the inventive cutting head, parts cut away to better illustrate the construction and parts in dotted lines to better illustrate the construction, as well, one cutter tip shown in full lines in impact position and in dotted lines in cutting position.

FIG. 3 is a view taken along the line 33 of FIG. 2 in the direction of the arrows.

FIG. 4 is a schematic view of a cutter tip holder show ing one relationship of the central axle receiving opening to the cutter tip slots.

FIG. 5 is a view similar to that of FIG. 4 but with the cutter tip holder axle opening in a second position.

FIG. 6 is a view similar to FIGS. 4 and 5, but with the cutter tip holder opening biased to a yet third position relative to the cutter tip slots.

FIG. 7 is an exploded perspective view from above of the frame assembly mounting the cutter head assembly.

Referring to FIGURE 7, sprocket 41 is driven by any suitable power source and is engaged by roller chain 42 and also engaging sprocket 43 carried by cutter head axle 44.

It should be noted that axle 44 mounting the cutter head assembly (to be described) at the front end of the gravel scratching machine, is angled at a substantial degree (preferably about 15) from the direction of travel thereof. This is accomplished by mounting the cutter head assembly at the front end of a skewed frame of suitable construction.

Turning to the mounting means for the cutter assembly, fixed to the sides of a forward frame are side plates 61 and 62 of equal length. Plates 61 and 62 have openings 63 and 64 therethrough adjacent the front ends thereof whereby to receive axle 44. Mounted on the hexagonally formed cutter head receiving portion 44a of axle 44 are a plurality of cutter head units generally designated at 65 and to be described in greater detail. Bearing carrying plates 66 and 67 are removably fixed to the outer faces of side plates 61 and 62 to receive axle 44 in rotation. One outer end of axle 44 is received in sprocket 43 for drive of the axle in rotation. Sprocket and chain guard 68 is fixed to the periphery of side plate 61 and gravel shield 69 is fixed to the inner face of side plate 61- and extends thereabove. Head guard 70 is fixed at its edge 71 to gravel shield 69 on the upper edge thereof and to a portion of the frame, not shown, by rearward extension 72.

Referring particularly to FIGS. 2-6, therein are shown the details of an individual cutter head, generally designated 65, a plurality of which are slidably mounted on the hexagonal portion 44 of axle 44a for rotation therewith. Each cutter head 65 comprises a pair of metallic plates 73 and 74, each having a circular central hub 73a and 74a, respectively. A hexagonal opening (or other form) precisely congruent to the hexagonal (or other cross-sectional) form 44a of axle 44 is formed through each hub 73a and 74a as at 7312 and 74b. A plurality of metallic separating members 75 space the plates 73 and 74 apart a desired distance, the members 75 being welded or otherwise fixedly attached to the plates 73 and 74. Plates 73 and 74 may each be recessed as at 75a over a portion of their contact with members 75, as desired.

Members 75 have a particular structure including, (following in the direction of rotation of the plates 73 with axle 44) a first surface 76 angled at a first angle or inclination to a radial line from the axle center and a second surface 77 angled at a second, greater angle or inclination to a like line. A plurality of openings '78 and 79 are formed through plates 73 and 74, respectively, the openings preferably being furnished with circumferentially raised portions 7 8a and 79a on the outer faces of plates 73 and 74. Bolts 80 engaged by nuts 81 are received in openings 78 and 79 for a purpose to be described.

A plurality of cutter tips or blades having body portions 82 adapted to slidably fit within the spaces between plates 73 and 74 and between adjacent connecting members 75 are pivotally mounted in said spaces or slots by bolts 80. The planes of the body members 82 of the cutter tips or blades thus extend parallel to the planes of plates 73 and 74. Connected to or integral with the outer edges of body members 82 are cutter flanges or blades 83 which extend in planes normal to the planes of members 82. The rear or following sides 82a of members 82 are preferably straight as shown whereby to successively abut surfaces 76 and 77 of separator members 75 in two operating positions to be described.

The position of openings 78 and 79 relative to surfaces 76' and 77 and the width of members 82 from the bolt openings 82b therein to the fiat following sides thereof are preferably so sized and adjusted that the following edges 82a may first abut against surfaces 76 radially inside of bolts 80 and by movement of blades 83 opposite the direction of rotation of the plates may secondarily abut, in portions thereof radially outside of bolts 80, surfaces 77. This is shown sequentially in full and dotted lines in FIG. 2. Functionally, this means that body members 82 cannot rotate any further in the direction of rotation of plates 73 and 74 than permitted by surfaces 76 and are limited in rotation away from the direction of rotation of the plates 73 and 74 by surfaces 77. operationally, there is a first impact position as in full lines in FIG. 2 where blades 83 strike the tar and gravel roofing and a secondary cutting position as shown in dotted lines in FIG. 2 where blades 83 shear through the tar and gravel backed by surfaces 77. The relative alignment of blades 83 to radial lines drawn from the center of axle 44 in the first position is preferably with the blades 83 tips aligned with radial lines running from the center of axle 44 through the centers of bolts 80 to the tips of blades 83. Furthermore, a line drawn at right angles to this line preferably finds blade 83 at approximately a 15 angle thereto for first impact. Secondly, with the blade having retreated to the dotted line position of FIG. 2, the toes of blades 83 preferably follow radial lines through the center of axle 44 and the centers of bolts 80 and are positioned slightly radially inwardly of the first positions of the toes of the blades whereby to have a certain amount of fall back and are also preferably at approximately 30 angles normal to the same radial line whereby to have retreated to a sharper attack angle than the original impact thereby 4- to minimize skid. Centrifugal force places the blades in the first position and impact drives them to the second.

These above relationships preferably are those of each cutter blade or cutter tip in each slot or recess between members 75.

Viewing the assembly of cutter heads on the axle 44, particularly in FIGS. 1 and 7, a number of operating relationships may be seen. In the first place, in the construction shown, there are a plurality of, here six, cutter tips to each cutter head. Secondly, adjacent cutter heads are staggered in the relationship of their slot openings and cutter tip spacings relative to one another so that, in effect, a six lead helix is created across the peripheral surfaces of the cutter heads. Finally, in the assembly shown, a plurality of, here twelve, cutter heads assemble on the hexagonal portion of the axle to make up the operative cutter head assembly. By virtue of this structure, as most readily is seen in FIG. 1, a plurality of, here three, cutters at any given impact instant are precisely aligned against the impact surface, the cutters impacting simultaneously only in cutter heads which are separated from one another by a plurality of other cutter heads. A typical width of a cutter blade or flange 83 is an inch, thus three swaths an inch wide are cut at any instant in instantaneous impact.

By spacing the individual cutters impacting simultaneously one from the other and staggering the cutters in the manner shown, together with the large mass of cutter head assembly in rotation, a maximum avoidance is achieved of large, sequential, spaced jars which would prevent following cutters from full engagement with the material being scratched. Bounce of the machine and vibration is also minimized this way. A further advantage of the helical arrangement is that it tends to lead the material which has been cut or scratched from left to right in the view of FIG. 1, with the cutter head assembly rotating in the direction shown by the arrow in FIG. 1.

The staggering of the cutter blades in the spiral or helical form shown also cuts down the required applied power to the cutter head assembly to drive the impacting blades through the tar and gravel. The width of individual cutter tips or blades 83 is such that there is no overlap between adjacent blades, but there is, neither, any substantial gap, width-wise, therebetween. The blades, after cutting the roof in the second rearward position are returned to the first forward position by centrifugal force. By locking the cutter tip in a maximum forward position in the direction of rotation of the plates 73 and 74 as to not pass the radial line previously designated, avoidance of riding the cutter tip over the gravel and tar is avoided. Yet another feature of the construction is that, as the cutter blades 83 bite into the tar and gravel, the angle of impact is such as to continuously sharpen the front edge of the blades 83 whereby the device is self-sharpening.

In operation, the cutter head assembly as seen in FIGURE 1 is set into rotation free of contact with the roof to be scratched and before driving of the scratcher in motion is begun whereby to minimize initial drag on the engine and to prevent the cutter teeth from immediately digging into the roof. The operator, after the cutter head assembly comes up to speed, then engages the power to the wheels of the device through any suitable transmission and the cutter head assembly may then be lowered into contact with the roof to start the scratching operation. The cutting head assembly runs in a direction of rotation opposite to the direction of forward motion of the machine. The helix action of the head, combined with angling of same from the direction of travel, facilitates throwing of the gravel and tar to one side and thereby achieves some windrowing.

FIGS. 4, 5 and 6 are schematic views showing the differing alignments of the hexagonal openings in the central hub in jacent cutter heads. Thus, in FIG. 4

(the hexagonal opening is greatly exaggerated for emphasis) and the hexagonal vertices are almost centered in the slots carrying the cutters. In the FIG. 5 cutter head (which would be to the right of the cutter head of FIG. 4 in the showing of FIG. 1) the hexagonal vertices are less centered in the direction of rotation of the cutter heads, while in FIG. 6, the hexagonal vertices are yet further displaced in the direction of rotation of the cutter heads. Note in all three views, FIGS. 4, 5 and 6, the vertices of the hexagonal opening are identically positioned, while the slot portions are varied, which would correspond to a fixed position on the axle 44. For convenience in replacement, the central hubs of plates 73 and 74 may be made replaceable with varying openin-g adjustments, if desired.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. A cutter tip holder for the cutter head of a roof scratching device comprising a circular plate mountable on an axle for rotation therewith,

said plate having a plurality of circumferential slots in the edge thereof extending substantially radially inwardly thereof,

a cutter tip body pivotally mounted along the length thereof in each of a plurality of said slots whereby to pivot therein forwardly and rearwardly with respect to the operating direction of rotation of the holder,

each cutter tip body comprising an elongate flat member substantially received in one of said slots and having a flat cutting flange attached to the outer end thereof,

the plane of extension of said cutting flange oriented substantially normal to the planes of extension of said plate and the elongate body of the cutter tip carrying same,

the width of said cutting flange greater than the slot width whereby said flange remains outside of said slot,

each cutter flange and cutter tip body having forward and following edges with respect to the operating direction of rotation of the holder,

the Wall of each cutter tip carrying slot following in the direction of rotation of said holder having a first relatively inward base positioned so as to contact the inward following edge of the cutter tip body in a first forwardly pivoted position thereof and limit forward rotation of the outer end of the cutter tip in the direction of operating rotation of the cutter tip holder,

said wall also having a second relatively outward face thereof positioned so as to contact the outward following edge of the cutter tip body in a second rearwardly pivoted position thereof and limit rearward rotation of the outer end of the cutter tip body in the direction opposite that of operating rotation of the holder,

the angle of outward extension of the cutter flange in the direction of holder rotation greater at the rearward rotation limit position of the cutter tip body than at the forward same.

2. A cutter tip holder for the cutting head of a roof scratching device comprising a pair of circular plates axially fixed to one another yet spaced therefrom for simultaneous axial rotation around a mounting axle,

a plurality of radially extending divider means positioned between said plates and next thereto,

said divider means forming between themselves a plurality of slots opening radially outwardly from said plates,

a cutter tip body pivotally mounted in each of a plu rality of said slots whereby to pivot therein forwardly and rearwardly with respect to the direction of rotation of the plates,

each cuttertip body comprising an elongate flat member having a flat cutting flange attached to the outer end thereof,

the plane of extension of said cutting flange oriented substantially normal to the plane of extension of said elongate tip body and also to the planes of extension of said plates,

the width of said cutting flange greater than the slot width whereby such cutter flange remains outside of said slot,

each cutter flange and cutter tip body having forward and following edges with respect to the direction of rotation of the plates,

each said plate divider means following a cutter tip body and slot therefor in the direction of rotation of said holder having at least two radially spaced face portions,

one relatively inward divider face portion positioned to contact the cutter tip body inward following edge and limit forward rotation of the outer portion of the cutter tip body of the direction of rotation of the plates,

a second relatively outward divider face portion positioned to contact the cutter tip body outward following edge and limit rearward rotation of the outer portion of the cutter tip body in the direction opposite to that of rotation of the plates,

the angle of outward extension of the cutter flange in the direction of plate rotation greater at the rearward rotation limit position of the cutter tip body than at the forward same.

References Cited by the Examiner UNITED STATES PATENTS 2,319,520 5/ 1943 Rypkema. 2,336,487 12/1943 Lewis et 21. 2,576,607 11/ 1951 Knudson et al. 2,680,606 6/ 1954 Bolton. 2,749,103 6/ 1956 Clemenzi. 2,923,536 2/ 1960 Marshall et a1. 3,022,055 2/ 1962 Allimann.

BENJAMIN HERSH, Primary Examiner. PHILIP ARNOLD, Examiner. 

1. A CUTTER TIP HOLDER FOR THE CUTTER HEAD OF A ROOF SCRATCHING DEVICE COMPRISING A CIRCULAR PLATE MOUNTABLE ON AN AXLE FOR ROTATION THEREWITH, SAID PLATE HAVING A PLURALITY OF CIRCUMFERENTIAL SLOTS IN THE EDGE THEREOF EXTENDING SUBSTANTIALLY RADIALLY INWARDLY THEREOF, A CUTTER TIP BODY PIVOTALLY MOUNTED ALONG THE LENGTH THEREOF IN EACH OF A PLURALITY FO SAID SLOTS WHEREBY TO PIVOT THEREIN FORWARDLY AND REARWARDLY WITH RESPECT TO THE OPERATING DIRECTION OF ROTATION OF THE HOLDER, EACH CUTTER TIP BODY COMPRISING AN ELONGATE FLAT MEMBER SUBSTANTIALLY RECEIVED IN ONE OF SAID SLOTS AND HAVING A FLAT CUTTING FLANGE ATTACHED TO THE OUTER END THEREOF, THE PLANE OF EXTENSION OF SAID CUTTING FLANGE ORIENTED SUBSTANTIALLY NORMAL TO THE PLANES OF EXTENSION OF SAID PLATE AND THE ELONGATE BODY OF THE CUTTER TIP CARRYING SAME, THE WIDTH OF SAIS CUTTING FLANGE GREATER THAN THE SLOT WIDTH WHEREBY SAID FLANGE REMAINS OUTSIDE OF SAID SLOT, EACH CUTTER FLANGE AND CUTTER TIP BODY HAVING FORWARD AND FOLLOWING EDGES WITH RESPECTG TO THE OPERATING DIRECTION OF ROTATION OF THE HOLDER, THE WALL OF EACH CUTTER TIP CARRYING SLOT FOLLOWING IN THE DIRECTION OF ROTATION OF SAID HOLDER HAVING A FIRST RELATIVELY INWARD BASE POSITIONED SO AS TO CONTACT THE INWARD FOLLOWING EDGE OF THE CUTTER TIP BODY IN A FIRST FORWARDLY POIVOTED POSITION THEREOF AND LIMIT FOR WARD ROTATION OF THE OUTER END OF THE CUTTER TIP IN THE DIRECTION OF OPERATING ROTATION OF THE CUTTER TIP HOLDER, SAID WALL ALSO HAVING A SECOND RELATIVELY OUTWARDLY FACE THEREOF POSITIONED SO AS TO CONTACT THE OUTWARD FOLLOWING EDGE OF THE CUTTER TIP BODY IN A SECOND REARWARDLY PIVOTED POSITION THEREOF AND LIMIT REARWARD ROTATION OF THE OUTER END OF THE CUTTER TIP BODY IN THE DIRECTION OPPOSITE THAT OF OPERATING ROTATION OF THE HOLDER, THE ANGLE OF OUTWARD EXTENSION OF THE CUTTER FLANGE IN THE DIRECTION OF HOLDER ROTATION GREATER AT THE REARWARD ROTATION LIMIT POSITION OF THE CUTTER TIP BODY THAN AT THE FORWARD SAME. 